Arc heater apparatus for chemical processing



y 1969 A. M. BRUNING ET AL 3,445,191

ARC HEATER APPARATUS FOR CHEMICAL PROCESSING Filed July 14, 19653,445,191 ARC HEATER APPARATUS FOR CHEMICAL PROCESSING Armin M. Bruning,Franklin Township, Export, and Peter F. Kienast, Pittsburgh, Pa.,assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., acorporation of Pennsylvania Filed July 14, 1965, Ser. No. 471,914 Int.Cl. Hb 7/18 US. Cl. 23-277 10 Claims ABSTRACT OF THE DISCLOSURE An archeater for chemical processing has a pair of axially spaced annularelectrodes producing an axially extending arc therebetween. Field coilsin the electrodes set up a magnetic field which causes the arc to movesubstantially continuously in an annular path around the electrodes.Means is provided for admitting a process gas at a large number ofperipherally spaced points whereby the process gas passes through thearc path and thence into the arc chamber and downstream toward thenozzle. Process gas may be admitted at a number of additional positionsaxially spaced along the arc heater, always at a large number ofperipherally spaced points. A quenching gas may be admit-ted through thearc path but at a position downstream of where the process gas isadmitted: a quenching gas may be admitted through a central aperture inthe plug closing the upstream end of the arc chamber at a positionactually upstream of the position where the process gas is admitted, butthe quenching gas moves downstream before mixing occurs. Very rapidquenching in a time of the order of a fraction of a microsecond isobtainable. Additionally, fluid may be introduced at axially spacedpositions at a plurality of peripherally spaced points to freeze therecombination product and prevent further undesired chemical reactions.

This invention relates to are heater apparatus for chemical processing,and more particularly to such are heater apparatus having improved meansfor the introduction of reactant and quenching materials.

Chemical reactions promoted by thermal energy have in the pastsuccessfully employed an arc source for heating or pyrolyzing a processgas. In many chemical reactions there is need for quenching immediatelyafter the reactant has been heated by the are or other means. Immediatequenching enables the recovery of specific chemical products prior totheir recombination or dissociation into the often times more stable butless desirable byproducts. Some reactions yield best results withquenching taking place only microseconds to milliseconds after heating,thus requiring close proximity between the quench zone and heating zone.

In the past no satisfactory way has been found of obtaining an immediatequench. For example, in British Patent 938,823 issued to E. I. du Pontde 'Nemours & Company, the first quenching material is introduced aconsiderable distance from the arc zone, representing a considerableelapsed time.

Our apparatus overcomes the limitations of the prior art and providesfor immediate quenching, by the immediate introduction of a quenchingmaterial either gaseous or liquid, or both, within microseconds, or evena fraction of a microsecond, after the process gas is decomposed.Further, the improved apparatus of our invention provides forintroducing either a gaseous or liquid quench or both at various timeintervals after the decomposition takes place, as required by someparticular chemical reaction or process to be carried out.

3,445,191 Patented May 20, 1969 This application is related to thecopending application of C. Hirayama et al. for Method and Equipment forthe Pyrolysis and Synthesis of Hydrocarbons and Other Gases and ArcHeater Apparatus for Use Therein, S.N. 446,012, filed Apr. 6, 1965, nowissued Patent 3,389,189; the application of P. F. Kienast et al. for ArcHeater Apparatus for Chemical Processing, S.N. 471,-914, filed July 14,1965; the application of A. M. Bruning et al. for Cross Flow Arc HeaterApparatus and Process for the Synthesis of Carbon, Acetylene, and OtherGases, S.N. 507,345, filed Nov 12, 1965; the application of D. A.Maniero et al. for Direct Conversion Chemical Processing Arc Heater,S.N. 527,789, filed Feb. 16, 1966 now issued Patent 3,284,782; and theapplication of D. A. Maniero et al. for Process for Hydrogen Cyanide andAcetylene Production in an Arc Heater Having a Rotating Arc, S.N.657,867, filed Aug. 2, 1967, all of the aboveidentified applicationsbeing assigned to the assignee of the instant invention.

In summary, our apparatus includes means forming an arc chamber in whichtwo substantially cylindrical electrodes spaced from each other have anarc therebetween, the two electrodes having magnetic field producingcoils disposed therein for producing a magnetic field transverse to thearc path which causes the arc to move substantially continuously aroundthe arcing surfaces of the electrodes. One end of the substantiallycylindrical arcing chamber is closed by a plug or closure member, andprocess gas is introduced into a substantially cylindrical passagewaybetween the plug and the inner wall of the arcing chamber. A firstquenching gas or liquid may be introduced through the aforementionedplug which has a passageway therein. In addition, a ring or heat shieldmember spacing the aforementioned two electrodes has annular headermeans therein, with means for introducing a quenching material, eithergaseous or liquid, through a plurality of spaced apertures around theentire periphery of the ring or spacing heat shield member. Anadditional and similar ring or spacer member is disposed downstream ofthe downstream electrode, between the downstream electrode and thenozzle, and this last-named spacer ring also has header means therein,and a plurality of apertures therearound communicating with the headermeans for introducing a spray or reactant into the gas as it moves pastthe downstream electrode toward the nozzle. Furthermore, the nozzle ofthe electrode has a plurality of apertures in the inner wall thereofcommunicating with a fluid passageway therein, for spraying a quenchingmaterial, which may be gaseous or liquid, into the process gas as it isexhausted from the nozzle. An extension to the nozzle provides forfurther spraying a cooling or quenching fluid into the heated gas at afourth downstream position representing a longer elapsed time intervalbetween the heating of the gas and the introduction of the last-namedquenching fluid. In addition to process gas being introduced around theaforementioned plug which closes one end of the arcing chamber, headermeans are provided for introducing gas on both sides of the spacermember between the two electrodes, and on both sides of the spacermember between the downstream electrode and the nozzle, so that theselast-named four annular gas headers, with a plurality of spaced borescommunicating with the interior of the chamber at spaced intervalsaround the entire peripheries thereof, provide ample means forintroducing a fluid or gaseous quenching material or materials into thechamber at a number of position with respect to the gas heating orpyrolyzing zone. In effect then a gaseous quench or a fluid quench maybe introduced into the process gas after heating at almost any desiredinstant, and with any desired elapsed time interval be tween thedecomposition of the gas and the introduction of the quench.

Accordingly a primary object of the invention is to provide new andimproved arc heater apparatus especially suitable for chemicalprocessing.

Another object is to provide new and improved arc heater apparatushaving new and improved means for introducing reactant and quenchingmaterials.

These and other objects will become more clearly apparent after a studyof the following specification, when studied in connection with theaccompanying drawing, in which the single figure thereof represents ourinvention according to the preferred embodiment thereof.

Referring now to the drawing for a more detailed understanding of theinvention, there is shown an arc heater generally designated 9 which isseen to be substantially cylindrical in shape and to have an outer wallportion formed of a cylindrical upstream electrode member generallydesignated 11, a ring member generally designated 12, a downstreamelectrode generally designated 13, and an additional ring membergenerally designated 14 spacing the downstream electrode 13 from adownstream closure and nozzle member generally designated 15, all ofthese enclosing an arc chamber generally designated 10. An additionalnozzle generally designated 16 is attached in a form or manner to extendthe length of the nozzle and the quenching or cooling exit passagewaytherethrough. The other end of the arc chamber is closed by a closuremember generally designated 17 which as seen is adapted to be fluidcooled from headers 171 and 176 and which also has a passageway 18therethrough for the introduction of a quenching material into the arcchamber 10. Arc 21 is seen taking place in the chamber 10 betweenelectrodes 11 and 13. Means for bringing a current to the arc heaterapparatus generally designated 9 is securely connected to electrodes 11and 13 and is symbolized by leads 23 and 24, which it is understood maybe connected to a suitable source of direct current potential, notshown, or to a source of single phase alternating current potential, notshown for convenience of illustration.

As previously stated, the apparatus is especially constructed to permitthe introduction of a reactant or process gas, and also to permit theintroduction at various points and at various times in the movement ofthe process gas through the arc heater of other reactants or quenchingmaterials which may be either gaseous or fluid. To this end an annularor cylindrical space 25 exists between the outer wall of the closuremember 17 and the inner wall of the electrode generally designated 11.In the electrode 11 there is a fluid or gas header which is annular inshape, the header being shown at 26, having a gas inlet 27 and having aplurality of spaced radial passageways, two of these being shown at 28and 29, communicating between heater 26 and annular space 25. Thesection of the arc chamber wall or electrode generally designated 11 isseen to comprise generally speaking two portions, an outer portion 31which may be of for example, steel, and may be of ferromagneticmaterial, and an inner portion 32 of, for example copper. The copperportion 32 is seen to have a thin wall portion 33 adjacent the arcchamber 10, and it is seen that directly behind the thin wall portion 33is a cylindrical passage 35 shaped generally to the contour of the wallportion 32. The passage 35, which as beforementioned is cylindrical inshape, may extend around the entire circumference of the wall portion,and is provided for the flow of cooling water or other fluid which mayenter the annular or ring shaped water passage or water header 37 by wayof inlet conduit 38 and exit from the annular ring-shaped water passage36 by way of exit conduit 39. The outer chamber wall portion 31 is seento have sealing means such as O-rings at 41, 42, 43 and 44 for providingseals between the outer section 31 and the inner section 32. Disposed inan annular recess 45 in portion 32 is a field coil 46 provided forassisting in setting up a magnetic field transverse to the arc path andto the path of current flow for providing a force on the arc in such adirection as to cause the arc to move substantially continuously in anannular path on the electrodes 11 and 13. As will be readily understoodby those skilled in the art, it is necessary to continually move the arcto prevent the intensely hot are spot from burning a hole in theelectrode with resulting escape of fluid into the arc chamber andpossible destruction of the electrode, or explosion within the chamber.It is seen that the outer wall contour of wall portion 33 comes to apeak at 48, overhanging the annular space 120 which separates the ringgenerally designated 12 from the cylindrical portion 11 on the adjacentside thereof. This annular peak 48 is provided to ensure opticalbaflling for the insulating ring member 113 and for O-ring 30, so thatdirect radiation from the arc 21 in the arc chamber 10, and direct radiation from heated gas in the vicinity of the are 21, do not fall upon theinsulating member 113 or the O-ring 30. Wall surface 50 is rounded andconforms very closely to the path of the magnetic flux in this area.

As seen from the figure, the aforementioned annular or ring-shapedpassageway exists between the wall of ring 12 and the adjacent wall ofcylindrical electrode 11. Near this annular passageway 120 and withinthe electrode 11 there is disposed an annular fluid header 121, havingan inlet 122, and having a plurality of passageways at spaced intervalsaround the entire electrode communicating between the header 121 and thering-shaped passageway 120, two of these communicating passageways beingshown at 123 and 124. This arrangement permits the introduction of gas,which may be either a portion of the process or reactant gas, or may begas deliberately introduced to quench or cool the heated gas in the arcchamber.

The electrode member generally designated 11 is spaced from andelectrically insulated from the ring member 12 by an insulating disc 19which terminates at its inner edge in the aforementioned O-ring 30.

The aforementioned ring member 12 which may also serve as a heat shield,may include two sections composed of different materials. The inner ringportion 214 may be composed of copper; the outer ring portion 212 mayhave an annular passageway 215 therearound for the passage of a coolingfluid, for example water, in two substantially semicircular pathsbetween a water inlet 221 and a water outlet 222. O-rings 217 and 218provide a seal for the fluid in passageway 215. A series of annulargroove-like passageways or fingers extend from the passageway 215 towardthe surface of ring portion 214 which faces the arc chamber 10, three ofthese annular fingers being shown at 231, 232 and 233, each of theannular fingers having a plurality of spaced bores extending therefromthrough the inner wall of the chamber around the entire periphery ofring member 12, the bores of finger 231 being designated 234, those ofannular finger 232 being designated 235, and those of finger 233 beingdesignated 236.

Spaced from the ring member generally designated 12 is theaforementioned downstream electrode generally designated 13, theelectrode 13 being spaced from and electrically insulated from the ring12 by an insulating disc 20 terminating in an O-ring 22. Disposedbetween the O-ring 22 and the annular or ring-shaped passageway 119between the wall of ring 12 and the adjacent wall of electrode 13 is aninsulating member 114 preferably composed of a highly heat resistantceramic, to optically shield the O-ring 22 from direct or reflectedradiation. The electrode 13 is generally similar to the aforementionedelectrode 11 and includes an outer portion 51 which may be steel orferromagnetic material, and an inner portion 52 with a thin wall portion53. Adjacent the wall portion 53 is a cylindrical cooling passage 55,having an inlet or header at 56 connected to inlet conduit 58, and anoutlet or header at 57 connected to outlet conduit 59. Sealing O-rings61 and 62 are provided, and a field coil 66 is provided as shown inrecess 65. The wall portion 53 also has a peak portion 68 for providingoptical bafiling for the insulating member 114 and O-ring 22. Wallsurface 60 is curved to the curvature of the magnetic field from coil66.

An annular gas header 237 in the electrode 13 has a gas inlet 23S and aplurality of passageways from the header communicating with the annularpassageway 119 between ring 12 and electrode 13 for bringing gas intothe passageway at a plurality of points at spaced intervals around theentire inner wall of the arc heater, this last named gas being either aprocess gas or a quenching gas. Two of these passageways are shown at239 and 240. On the other side of the electrode 13 is an additional gasheader 241 having a gas inlet 242 and a plurality of passagewaystherefrom at spaced intervals around the periphery of the electrodecommunicating with the annular space 246 between the electrode 13 andthe adjacent ring 14, two of the aforementioned passageways being shownat 243 and 244.

Disposed adjacent the aforementioned downstream electrode 13, andbetween the downstream electrode 13 and the aforementioned closure andnozzle member generally designated 15, is an additional ring membergenerally designated 14, which is substantially similar to thepreviously described ring 12. Ring 14 is spaced from and electricallyinsulated from the electrode 13 by insulating disc 192 terminating in anO-ring 193. Between the O-ring 193 and located in the aforementionedannular space 246 is a ceramic ring of highly heatresistant material194. As previously stated, the ring member 14, which may also serve as aheat shield, has an outer portion 195 and an inner portion 196 composedof copper or other highly heat conductive material, the outer portion195 having an annular fluid header or passageway 197 therein forproviding two substantially semicircular paths for a fluid through thering, the fluid header 197 communicating with a fluid inlet 198 and asubstantially oppositely disposed fluid outlet 199. O-rings 201 and 202provide sealing between the two portions of the ring, and the annularfluid header 197 has three annular fingers 203, 204, 205, extendingtherefrom, each of the fingers or annular passageways having a pluralityof bores therefrom to the inside of the arc chamber, the bores passingthrough the narrow wall portion, the bores of finger 203 beingdesignated 206, those of finger or annular passageway 204 beingdesignated 207, and the bores of passageway 205 being designated 208.

The aforementioned closure or nozzle member 15 is generally disc-shaped,with a nozzle opening 140 substantially centrally disposed therein,member 15 being spaced from and electrically insulated from theaforementioned ring 14 by insulating disc 141 terminating in O-ring 142with a ceramic annular wafer 143 disposed in the space 144 between thewall of ring 14 and the adjacent wall of member 15. Member 15 has anannular gas header 146 with a gas inlet thereto 147 and a plurality ofsmall passageways communicating between the annular gas header 146 andthe space 144, two of these passageways being shown at 148 and 149. Anannular fluid header 151 with a fluid inlet 152 communicates by way ofsubstantially U-shaped or cylindrical passageway 153 with a fluid outletheader, not shown for convenience of illustration, the fluid outletheader being located in the nozzle portion generally designated 16.Cylindrical passageway 153 has a plurality of spaced bores therefrom ingenerally ring-shaped form extending through the wall of the nozzle sothat a quenching fluid may be introduced into gas passing through thenozzle. These bores are shown at 155 and may be in the pattern ofaxially spaced circles with a plurality of bores at spaced intervalsaround each circular position.

The aforementioned nozzle 16 forms in effect a continuation of thenozzle passageway 140, and includes in addition to the generallycylindrical portion 157 a flange 158 and includes an annular groove 159for the O-ring 160.

A passageway 162 through the aforementioned electrode generallydesignated 11 is provided for bringing leads to the aforementioned fieldcoil 46; it will be understood that a similar passageway, not shownbecause it is not in the particular cross-sectional plane selected forillustration, is provided for the aforementioned field coil 66, or leadsmay be made internally between the coils if desired. The leads to thecoil 46 are shown at 163.

The aforementioned closure member for the lefthand end of the arcchamber 10, as seen in the figure, is generally designated 17 andcomprises a flange portion 166 electrically insulated from electrode 11by an insulating disc 167 terminating in O-ring 168; the plug membergenerally designated 17 as aforementioned has an axially extendingpassageway 18 with a flaring throat portion 169 on the inner endthereof, and is provided for bringing a quenching material, preferably agas, into the arcing chamber very close to the exit of the anularpassageway 25 through which, as aforementioned, the process gas isadmitted to the chamber. As a result of passageway 18 and throat portion169, a very short time interval of the order of a microsecond or perhapsless may elapse between the time that the process gas is pyrolyzed bythe are 21, and the time that a quenching fluid or quenching gas isintroduced therein, when this is desirable to obtain the desiredrecombination product in accordance with the process and chemicalsemployed. Plug 17 contains two annular water headers, one of these beingshown at 171 communicating with inlet passageway 172, the water header171 connecting with a cylindrical shaped fluid passageway 173 whichextends near the surface 174 of the plug which is exposed to radiationfrom the arc, thereby providing for cooling the same and transferringheat flux away from the same; thence the water flows down cylindricalpassageway 175 to annular water header 176 communicating with wateroutlet 177.

It will be understood that any convenient means, not shown forconvenience of illustration, may be pro- -vided for applying clampingforces between the outer surface of the flange 166 and the flange 158 ofnozzle 16 to clamp these two together and thereby apply clamping forcesto the remainder of the structure. In addition, insulated clamping ringsmay be mounted against the outer side surface of electrode 11, and theoutside annular surface of nozzle member 15, and clamped by insulatingbolts or other convenient means, to hold the electrode 11, ring 12,electrode 13, ring 14 and nozzle member 15 securely together.

In the operation of the above described apparatus, process gas, forexample a hydrocarbon, for example methane, may be introduced throughgas inlet 27, flowing into annular gas header 26 which communicates by anumber of radially extending passageways 29 with the cylindricalpassageway 25, gas exiting from the cylindrical passageway 25 very nearthe are 21 and immediately or substantially immediately passing into theheating zone of the arc. From the general area of the are, representedby the disc-like zone traversed by the arc 21 as it moves in a circularpath between the electrodes, gas flows downstream past the downstreamelectrode 13, past the downstream ring or heat shield 14, into thecentral aperture of the nozzle, and thence out the exit end of thenozzle, not shown for convenience of illustration. If it is desired toquench or cool the gas heated and dissociated by the are 21 byintroducing and adding another, cooler gas to cool the entire mixture toa temperature at which some desired product is in a stable equilibriumin proportions of substantial magnitude, then the cooling gas may beintroduced into the aforementioned passageway 18, or the cooling gas maybe introduced through gas inlet 122 to gas header 121 and thence exitthrough many spaced radially extending oblique passageways 123 and 124,coming out near the peak 48 of electrode 11 and mixing with the gasheated by the are. In like manner,

gas may enter the inlet 238, pass around annular gas header 237 and outthe plurality of spaced passageways 239 and 240, exiting into the gasheated zone near the aforementioned peak 168, this last named gas beingintroduced only a very small interval of time, in the order of amicrosecond or perhaps less, after the gas introduced through passageway120. The gas then moves further downstream in the chamber of the archeater 10. As previously stated, the apparatus is constructed toaccommodate the introduction of a fluid or liquid quench if desired, andthis may be done through the passageways 231, 232 and 233 communicatingwith fluid header 215 and with the aforementioned holes 234, 235 and236, bringing the fluid into the chamber at spaced intervals around theentire inner wall of the chamber.

From the area of the arc zone itself, the gas passes in a right-handdirection through the chamber 10, past the aforementioned holes 206, 207and 208 where a further fluid quenching material may be introduced intothe gas by way of inlet 198, and thence through the nozzle opening 140where still a further fluid may be introduced by holes 155. It is alsoseen that there are additional places for introducing a quenching gas,for example by way of inlet 242, header 241 and passageways 243 and 244,and a short time interval later by way of gas inlet 147, header 146 andspaced passageways 148 and 149. In effect then substantially any timeinterval may be selected to introduce the quench gas and/or fluid intothe process gas, depending upon the particular chemical composition ofthe gas and the particular speed at which an equilibrium condition iscaused to exist at which the desired product is present in substantialproportion.

If desired, where it is not necessary or desirable to introduce a fluidquenching material into the chamber 10, the passageways 234, 235 and 236communicating with annular fingers or passageways 231, 232 and 233 maybe eliminated, as may be the bores or passageways 206, 207 and 208communicating with fingers 203, 204 and 205, in which case fluid flowingin the annular headers 215 and 197 serves merely to cool the portions ofthe rings which face the intensely hot gases and radiation of the arcchamber 10.

If desired, separate inlet and outlet headers may be provided for thetwo portions of the nozzle, so that individual control can be maintainedover the gas or fluid coming through holes 155 in the member 15, andindividual control may be maintained over the gas or fluid coming intothe nozzle through the corresponding holes in the nozzle generallydesignated 16.

The axially extending passageway 18 in member 17 may be omitted where itis not desired to introduce gas through the plug, or as will be readilyunderstood, the left-hand end of the passageway 18 may be closed bysuitable closure means, not shown for convenience of illustration, whenit is not desired to use the passageway.

In like manner any of the inlets or outlets 27, 39, 38, 122, 221, 222,238, 58, 59, 242, 199, 198, 147 or 152 may be closed or plugged by anysuitable means, where it is not desired to use the particularpassageways for the injection of a process or quenching material, be ita gas or a liquid.

There has been provided, then, apparatus well suited to accomplish theobjects of our invention, which were to provide arc heater apparatushaving means for introducing a quench either gaseous or liquid or both,at substantially any selected time interval extending from a fraction ofa microsecond to a few milliseconds after the process gas is heated bythe electric are 21 to a temperature at which dissociation takes place.

Whereas we have shown and described our invention with respect toapparatus which gives satisfactory results, it should be understood thatchanges may be made and equivalents substituted without departing fromthe spirit and scope of the invention.

We claim as our invention:

1. Arc heater apparatus for chemical processing having a pyrolyzing zonein which a selected process gas is decomposed at a variable temperaturein accordance with variations in the are power and the mass flow rate ofgas through the arc heater, and in which the pyrolyzed gas must bequenched in a predetermined time which varies with different processgases, to a predetermined temperature which varies for different desiredrecombination products comprising, in combination, means forming an arcchamber, the chamber forming means including first and second spacedannular electrodes each having passageways therein near the surfaceadjacent the arc chamber for the flow of cooling fluid, the secondelectrode being the downstream electrode, means connected to the firstand second electrodes for producing and sustaining an arc therebetween,means for producing a magnetic field in the arc chamber of a magnitudeand direction to cause the are between the first and second electrodesto move substantially continuously in an annular path around the firstand second electrodes, closure means for the end of the chamber adjacentthe first electrode and having a passageway therein for the flow ofcooling fluid, the closure means having a passageway extendingtherethrough for bringing a quenching gas into the chamber, meansforming a cylindrical passageway around the closure means for admittinga process gas into the chamber in a cylindrical path of substantiallythe same diameter as the cylindrical path of the arc, the process gasentering the chamber near the arc, a first ring member disposed betweenthe first and second electrodes and having an annular passageway thereinfor the flow of cooling fluid, an exhaust nozzle member forming anexhaust vent and having a generally cylindrical passageway therein forthe flow of cooling fluid, and a second ring member disposed between thesecond electrode and the nozzle member and having an annular passagewaytherein for the flow of cooling fluid, the first ring member havingaxially and peripherally spaced holes therein communicating with thecooling fluid passageway therein for injecting a quenching fluid intothe gas in the chamber over an area substantially coextensive with thatdefined by the cylindrical arc path, the second ring member havingaxially and peripherally spaced holes therein communicating with thecooling fluid passageway therein for injecting an additional fluid intothe gas in the chamber adjacent the second ring member, the nozzlemember having axially and peripherally spaced holes thereincommunicating with the cooling fluid passageway therein for injecting afurther quenching fluid into the gas mixture as it passes through theexhaust vent.

2. Are heater apparatus for chemical processing having a pyrolyzing zonein which a selected process gas is decomposed at a variable temperaturein accordance with variations in the are power and the mass flow rate ofgas through the arc heater, and in which the pyrolyzed gas must bequenched in a predetermined time which varies with different processgases to a predetermined temperature which varies with different desiredrecombination products comprising in combination, means forming an arcchamber, only two electrodes consisting of first and second spacedannular electrodes disposed in the arc chamber, the second electrodebeing the downstream electrode, means for producing and sustaining anare between the first and second electrodes, means for causing the arcto move substantially continuously in an annular path around and betweenthe first and second electrodes, means for introducing a process gasinto the arc chamber in a substantially cylindrical path upstream of thefirst electrode and near the annular arc path, said are pyrolyzing theprocess gas, means for introducing a quenching gas into the chamberupstream of the first electrode but at a position farther from theannular arc path than that at which the process gas is introduced, thequenching gas acting to cool the pyrolyzed gas a short time interval ofthe order of a microsecond after pyrolysis takes place, and nozzleexhaust means for the arc chamber.

3. Arc heater apparatus for chemical processing having a pyrolyzing zonein which a selected process gas is decomposed at a variable temperaturein accordance with variations in the are power and the mass flow rate ofgas through the arc heater, and in which the pyrolyzed gas must bequenched in a predetermined time which varies with different processgases to a predetermined temperature which varies for different desiredrecombination products comprising, in combination, means forming an arcchamber, first and second spaced annular electrodes disposed in thechamber, means for producing an arc between the first and secondelectrodes, means for causing the arc to move in a substantially annularclosed path substantially continuously around and between the first andsecond electrodes, the second electrode being the downstream electrode,nozzle means disposed near the second electrode, means for introducing aprocess gas into the chamber near the first electrode, means forintroducing a quenching gas into the chamber near the first electrodebut downstream of the position whereat the process gas in introduced,means for introducing a quenching fluid into the chamber between thefirst and second electrodes, and means for introducing an additionalquenching fluid into the gas mixture as it passes through the nozzlemeans.

4. Arc heater apparatus for chemical processing having a pyrolyzing zonein which a selected process gas is decomposed at a variable temperaturein accordance with variations in the are power and the mass flow rate ofgas through the arc heater, and in which the pyrolyzed gas must bequenched in a predetermined time which varies with different processgases to a predetermined temperature which varies for different desiredrecombination products comprising, in combination, means forming an arcchamber, the means including first and second spaced annular electrodespartially defining the arc chamber, means for bringing a current to thefirst and second electrodes to produce and sustain an arc therebetween,the chamber forming means including magnetic field producing means forproducing a magnetic field which causes the arc to move substantiallycontinuously in a substantially annular path around and between theelectrodes, the second electrode being the downstream electrode, firstring and fluid header means disposed between the first and secondelectrodes, nozzle means including a nozzle opening, second ring andfluid header means disposed between .the second electrode and the nozzlemeans, plug means at the end of the chamber opposite to the nozzlemeans, the plug means having a passageway extending therethrough adaptedfor bringing a first gas into the chamber, the plug means having apassageway therearound adapted for bringing an additional gas into thechamber and introducing the additional gas into the chamber in anannular path between the plug means and the first electrode, meansforming a passageway adapted for introducing other gas at a large numberof peripherally spaced points between the first ring and fluid headermeans and the first electrode, gas inlet means forming a fourthpassageway adapted for bringing further gas into the chamber andintroducing the last-named gas between the first ring and a fluid headermeans and the second electrode at a large number of peripherally spacedpoints, gas introducing means forming a fifth passageway adapted forbringing still further gas into the chamber and introducing thelast-named gas between the second electrode and the second ring andfluid header means at a large number of peripherally spaced points, andgas introducing means forming a sixth passageway adapted for bringing anancillary gas into the chamber and introducing said last-named gas at alarge number of peripherally spaced points in the area between thesecond ring and fluid header means and the nozzle means, at least twopassageways spaced from each other being utilized to bring process andquenching gases into the chamber, said two passageways being selected inaccordance with the composition of the process gas and the compositionof the desired recombination product.

5. An arc heater for chemical processing comprising means forming an arcchamber, said means including a pair of axially spaced annularelectrodes with a ring shaped heat shield therebetween, exhaust meansfor the arc chamber, the electrodes being adapted to be connected toterminals of opposite polarity respectively of a source of potential toproduce and sustain an are therebetween, the arc extending substantiallyparallel to the longitudinal axis of the chamber, magnetic field coilmeans disposed in both electrodes and adapted to be energized to set upa magnetic field which causes the arc to rotate and form a substantiallycylindrical axially extending arc path between electrodes, means forintroducing a process gas at a plurality of peripherally spaced butsubstantially axially aligned points adjacent the upstream end of thecylindrical arc path, the arc having a predetermined power and the gasflow rate being such that the process gas is pyrolyzed by the are at apredetermined temperature, the desired recombination product being onewhich requires the process gas to be quenched in a time of the order ofmicroseconds to a predetermined temperature, and means for introducing acooling quenching gas at a plurality of peripherally spaced butsubstantially axially aligned points also adjacent the cylindrical arcpath but downstream of the first named plurality of peripherally spacedpoints.

6. An arc heater for chemical processing comprising means forming an arcchamber, said means including a pair of axially spaced annularelectrodes with a ring shaped heat shield therebetween, exhaust meansfor the arc chamber, the electrodes being adapted to be connected toterminals of opposite polarity respectively of a source of potential toproduce and sustain an arc therebetween, the arc extending substantiallyparallel to the longitudinal axis of the chamber, magnetic field coilmeans disposed in both electrodes and adapted to be energized to set upa magnetic field which causes the arc to rotate and form a substantiallycylindrical axially ex tending arc path between electrodes and adjacentsaid ring shaped heat shield, the ring shaped heat shield having aplurality of axially and peripherally spaced holes therein communicatingwith at least one annular fluid passageway within and extendingsubstantially around the entire periphery of the ring shaped heatshield, one end of the arc path being the upstream end and the other endof the arc path being the downstream end, means for introducing aprocess gas into the arc chamber in a generally cylindrical path notfarther downstream than the cylindrical arc path, the process gas beingpyrolyzed by the arc, and means for introducing a quenching fluid intothe arc chamber through said plurality of axially and peripherallyspaced holes at positions adjacent the cylindrical arc path to quenchthe pyrolyzed gas to a predetermined temperature.

7. An arc heater for chemical processing comprising means forming an arcchamber, said means including a pair of fluid-cooled axially annularelectrodes with a ring-shaped heat shield therebetween, the ring-shapedheat shield having an annular passageway therein for the flow of coolingfluid therein, exhaust means for the arc chamber, the electrodes beingadapted to be connected to terminals of opposite polarity respectivelyof a source of potential to produce and sustain an arc therebetween, theare extending substantially parallel to the longitudinal axis of thechamber, magnetic field coil means so mounted with respect to theelectrodes that a magnetic field is set up which causes the arc torotate substantially continuously and form a substantially cylindricalarc path between electrodes, means for introducing a process gas at aplurality of spaced points axially within the cylindrical arc path andnear the upstream end thereof, the are having a predetermined power andthe gas flow rate being such that the process gas is pyrolyzed by thearc and a predetermined average pyrolyzed gas temperature produced, thedesired recombination product being one which requires the process gasto be quenched in a predetermined time to a predetermined temperature,and means for introducing a cooling quenching gas at a plurality ofperipherally spaced points also axially within the cylindrical arc pathbut near the downstream end thereof, the ring-shaped heat shield havinga plurality of axially and peripherally spaced holes thereincommunicating from the arc chamber to the fluid flow passageway thereinwhereby an additional quenching material in the form of a fluid isintroduced into the arc chamber over a substantial portion of the axialextent of the cylindrical arc path.

8. An arc heater for chemical processing comprising means forming an arcchamber, said means including a pair of axially spaced annularelectrodes with a ringshaped heat shield therebetween, the electrodesbeing adapted to be connected to terminals of opposite polarityrespectively of a source of potential to produce and sustain an arctherebetween, the are extending substantially parallel to thelongitudinal axis of the chamber, magnetic field coil means so mountedwith respect to both electrodes that a magnetic field is set up whichcauses the arc to rotate and form a substantially cylindrical arc pathbetween electrodes, means for introducing a process gas into the chambersimultaneously at a large number of peripherally spaced points wherebysubstantially all of the process gas passes through the arc path, thedwell time of any portion of the process gas in the arc path beingsubstantially uniform whereby the process gas is heated and pyrolyzed ata substantially uniform temperature throughout, and means forintroducing a quenching fluid into the chamber at another large numberof peripherally spaced points simultaneously axially selected inaccordance with the rate of gas movement through the are heater wherebyat least a large portion of the pyrolyzed gas is substantially uniformlycooled to a temperature at which a desired recombination product ispresent in substantial proportion.

9. Are heater apparatus for chemical processing according to claim 8including in addition still further means for introducing an additionalquenching fluid into the chamber simultaneously at another large numberof peripherally spaced points all axially downstream of the first namedmeans for introducing a quenching fluid, the additional quenching fluidinhibiting further chemical recombination and inhibiting the formationof undesired recombination products.

10. Arc heater apparatus for chemical processing according to claim 8including in addition still further means for introducing an additionalquenching fluid at high axial velocity upstream of the cylindrical arcpath and from a position substantially at the axial center of thecylindrical arc path whereby the additional quenching fluid does notsubstantailly interfere with the pyrolysis of the process gas but ismixed with the pyrolyzed process gas only after pyrolysis to a uniformtemperature is substantially completed.

References Cited UNITED STATES PATENTS 2,952,706 9/1960 Lipscomb 23277 X3,149,222 9/1964 Giannini et al. 2l9-121 X JAMES H. TAYMAN, 111.,Primary Examiner.

U.S. Cl. X.R.

